1. Field of the Invention
The present invention relates to an automatic focusing camera which controls focusing by producing plural information for focus adjustment from the object field.
2. Related Background Art
In conventional automatic focusing cameras, the information for focus adjustment (distance measuring information or defocus information) is produced by projecting light from a light-emitting unit to an object positioned in the center of the object field determined by the view finder and receiving the light reflected from said object, but, there cannot be obtained information for focus adjustment, in case of photographing with an image frame composition with the main object not positioned in the center, thus resulting in a so-called central defocus picture.
In order to prevent failure in the control resulting from such central defocus, there is already realized a so-called multi-focus camera in which plural light-emitting elements are provided for producing information for focus adjustment in plural positions in the object field, and also the present applicant proposed a similar camera in the U.S. application Ser. No. 204,905 dated Jun. 10, 1988, now U.S. Pat. No. 4,908,646, issued Mar. 13, 1990.
However, such camera designed to produce plural information for focus adjustment from the object field may still result in such central defocus if the position of the camera is moved, since the plural light-emitting elements are arranged on the assumption that the position of the camera is constant at the photographing operation.
For example, when plural light-emitting elements are arranged in a horizontal row in the usual photographing position of the camera, if the camera is turned by 90.degree. so that said plural light-emitting elements are arranged vertically at the center of the object field and if main objects are positioned at left and right in said object field, there cannot be obtained the focus adjusting information for such objects and there is again encountered the central defocus phenomenon.
In order to prevent such central defocus phenomenon resulting from change in the camera position, it has been proposed to distribute a large number of light-emitting elements over a relatively wide area including the center of the object field.
However, the use of such many light-emitting elements requires complex processing for selecting the information finally used in focusing control from many focus adjusting information from said light-emitting elements, thus resulting in an elevated cost due to a complex circuit structure if said processing is achieved by hardware, or a longer time required for such selection if said processing is achieved by software.